I am a bit troubled to see the two forms exist (at least on jisho). According to [this article](https://selftaughtjapanese.com/2018/06/14/the-correct-way-to-describe-a-negative-state-using-%E3%81%9D%E3%81%86-sou-%E3%81%AA%E3%81%95%E3%81%9D%E3%81%86-vs-%E3%81%AA%E3%81%9D%E3%81%86-nasasou-vs-nasou/) , the rule 4 described there would imply that the first one is correct. However, the second one seems to be the “natural” form if we follow the usual conjugation of い adjectives.
Is both forms are correct? If so, do they convey the same meaning?
2 comments
The first one is technically correct. It is not uncommon to hear the second one though due to overgeneralising the ない > なさそう rule .(another example might be できなさそう instead of できなそう)
When the stem of the adjective consists of one mora, you insert さ to conjugate with そう. e.g. よ-い→よ-さ-そう / な-い→な-さ-そう. Otherwise, you technically don’t. e.g. できな-い→できな-そう.